Treatment of clays



TREATNIENT OF CLAYS William E. Brown, Gibsonia, and Clifford R. Giacobine,

Oakmont, Pa., assignors to Gulf Research & Development Company, Pittsburgh, Pa., a corporation of Delaware No Drawing. Application November 18, 1954, Serial No. 469,856

19 Claims. 01. 252-855 This invention relates to a process of treating bodies comprised wholly or in part of clays, including clay-like materials, for the purpose of maintaining and/or restoring the permeability to fluids of such bodies and renden'ng them stable toward disruption by mechanical and/or chemical forces. More particularly, this invention relates to a process of treating bodies comprised wholly or in part of clays, including clay-like materials, subject to swelling and/or dispersion, with subsequent loss of permeability and reduction in mechanical strength, for the purpose of maintaining and/ or restoring the permeability to fluids of such bodies and rendering them stable toward disruption by mechanical and/or chemical forces.

Clay-containing bodies often are substantially impermeable or have a low permeability to fluids or lose some or all of the permeability they may possess when they are subjected to the action of liquids such as water, certain brines, emulsions containing water or certain brines, etc. Treatment of such clay bodies in accordance with the process of this invention will render them permeable, prevent a reduction in fluid permeability and/or restore fluid permeability to those clay bodies in which it has been lost. As a result of the treatment the resistance of the clay bodies to mechanical and/or chemical disintegration will also be substantially increased.

The clay or clay-like materials which can be treated in accordance with our invention can include any natural geologic formations or artificial formations such as railroad or highway embankments, road beds and road surfaces, automobile parking areas, areas for outdoor sports, storage areas, military installations, etc. Included also among the materials which can be treated to improve or maintain their permeability and their physical and/or chemical stability are manufactured articles containing clays or clay-like materials. As an example, but without being limited thereto, this process can be employed to treat articles cast, extruded or otherwise formed from clay to increase their mechanical strength prior to and/ or after firing.

The process of this invention has particular applicability in the treatment of natural geologic formations for the purpose of preventing or correcting the loss in permeability thereof caused by swelling and/or dispersing of the clay contained therein, preserving the approximate geometry of the grains of the formation, maintaining the pore distribution of the formation and firming the formation if it is uncemented or poorly cemented. More specifically, this invention is especially advantageous in the treatment of a clay-containing formation adjacent a borehole in wells in order to increase, maintain and/or restore the permeability of the formation by rendering the clay contained therein resistant to swell- United States Patent'o Patented Sept. 4, 1956 ing, disruption and/or migration, and also to shrink essentially irreversibly the hydrated, swollen clay which may be present in said formations adjacent wells producing fluids, such as hydrocarbons, water, etc., or in wells which are used to inject such fluids into a geologic formation. The clay in the formation can be that which was present originally, or it can be clay which was introduced into the formation in the process'of creating the borehole, e. g., by the use of a clay-containing drilling mud, or in subsequent operations.

The clay originally present in the formation can reduce the permeability of the formation by swelling and/or migrating to form bridges or blocks in the pores of the formation or in perforations in casing, screens, etc., used in well completions, as a result of contact of said clay with aqueous liquids such as water, certain brines, emulsions containing water or certain brines, etc. This liquid can be introduced into the formation as drilling mud filtrate, injection water, Water from leaks in or behind the casing, or ground water associated with the formation. Of particular concern in the case of introduced clay is that clay which, as a component of the drilling mud, invades the formation during the drilling of the borehole. High swelling montmorillonite is often used in drilling muds, among other reasons, because of its ability to create a low permeability filter cake on the formation. Under some conditions, a low permeability zone is created within the formation in the vicinity of the borehole from invasion by the drilling mud. In addition, if the mud filter cake is not removed completely when drilling has been completed, it forms a barrier to the flow of fluid into or out from the formation. The

invention disclosed and claimed herein will shrink the dickite, and halloysite; the hydrous-mica group such as hydrobiotite, glauconite, illite and bramallite; the chlorite group such as chlorite and chamosite; clay minerals not belonging to the above groups such as vermiculite, attapulgite, and sepiolite; and mixed-layer varieties of the above minerals and groups. The clay content of the formations can be comprised substantially of a single species of clay mineral, or of several species, including the mixed-layer types of clay. Of the clay minerals commonly encountered in the drilling of wells in natural geological formations which can be productive of the difliculties herein noted and which can be treated effec tively in accordance with the present invention are clay minerals selected from the class consisting of the montin bulkvolume with or without dispersing, disi tegrating or otherwise becoming disrupted when subjected to contact with aqueous solutions such as water, certain brines, etc. Certain clays can also disperse, disintegrate or otherwise become disrupted without swelling in the presence of aqueous solutions such as water, certain brines, emulsions containing water or certain brines, etc. Some clays in the presence of such aqueous solutions will ex- :pand and be disrupted to the extent that h y will b om unconsolidated and move into a borehole. which consist largely ofrclay can develop pressures on the Format on order of several thousand pounds per square inch upon ab- ,sorbing water in a confined space.

The clay materials defined above occur as minute, plate-like, tube-like and/.01 fiber-like particles having an extremelylarge surface area compared to that of an equivalent quantity of 'a granular material such as sand. I This combination of small size and great surface area results in a high surface energy with attendant unusual surface properties and extreme aihnity for surface-active agents. The structure of some of these days, as for instance montmorillonite, can be pictured as a stack of sheet-like three-layer lattice units which are weakly bonded to each other and which are expanded in the --c crystallographic direction by 'water or other substances rwhioh can penetrate between the sheets and separate them.

All clay minerals have ion-exchange properties. Thus, for example, montmorillonite has a cation-exchange .capacity of from about :90 .to 130 :rnilliequivalents per 100 grams :of pure clay, illite :from about 20 .to 40 milliequiv- 'alents, and kaolinite from about .to milliequivalents. Under ordinary :oil-well conditions the ion-exchange reactions between the clays and substances associated with the bare generally found outhe base-exchange position or site roan be mentioned sodium, potasium, calcium, magnesium,

--iron,;hydrogen, .etc. These cations are believed to :be held :.-to the clay SHI faGGbYdOI'llCifQICGS.

The oations occupying the base-exchange sites .on the .clay can be those originally present ;or cations finding their way :to the base-exchange position firom the .liquids in :contact therewith. Accordingly, the nature and connentrationsvof ions in the :water .in contacts-with the clay can :determine the :cations occupying :the baserexchange :sites. In most oil well formations, :the naturalwaters associated therewith :contaiu .sodium'sas the predominant cation, with calcium,v magnesium 'androthencations present in-much smaller .quantities. Since the base-exchange positions :on the 1clayxareoccupied -by. cations, in manycases :the; cation will be sodium when natural ground gwaters such :as those described above are associated therewith. fUnffortunately, however, .as for example in the case of the sodium form-of.montmorillonite,"these clay minerals swell in thezpresence of water'or certain'brines and can, insome instances; exert pressures up to thousands .of-pounds per 'square inch. T hus, dependent upon the-vamountof water :absorbed, the clay can change to a rigid paste or :a gelatinousnnass, or if sufficient w-aterispresent, the-clay'can disperse completely into the aqueous phase.

We havefound that the difiiculties notedabove can be substantially reducedan-d a clay body can be=stabilized to-impart or maintain satisfactory permeability to fluids, :improved mechanical strength-and increasedresistanceto 'chemicalattack by treating :such clay body-with substituted ammonium ions derived from :aromatic nitrogen "compounds selected from the group 'consisting-of=N,-N-di- -methylbenzyl amine, -dibenzylamine, diphenylguani'dine,

'l, 3-di-o.-tolylguanidine, 'o-dimethyl aminomethylphenol, o-

r'dirnethylaminomethyl-p-t-butylphenol, o-dimethylamino- 4 methyl-p-l,1,3,3-tetrarnethyl-n-butylphenol, and 2,4,6-tri- (dimetliylaminornethyl)phenol. 'While the substituted ammonium ions defined above are eifective clay-stabilizing agents, the parent basic nitrogen compounds fromwhich the substituted ammonium ions are derived have essentially no clay-stabilizing action.

The substituted ammonium ions can be obtained, among.

other ways, from salts prepared by reacting an appropriate basic nitrogen compound of the class described with an acid, preferably one whose anionic component will not form a precipitate with ions associated with substances such as aqueous fl-uids with the substituted ammonium salt may come in contact. Thus, if the fluids contain a significant concentration of alkaline earth ions, it is inadvisable to employ salts whose anionic component may be sulfate, oxalatefetc since a precipitate'can result. Among the compounds which can be employed in prep n th sa t hydrochloric aci hyil-sohr te s nitric acid, lactic acid, citric acid, salicylic acid, etc., lower fiatty acidssuch as formic, a cetie, propionic, etc., and methyl bromide, ethyl bromide, isop'ropyl iodide, etc. Among the salts which are satisfactory for use in accord- --ane th the pre e n n n e NN- fih ethflhfl amin d och o d N di,me hy eh lami e h d ob om d Nfladim h lb nz am he ac tat NN-rlime hyl nzylam h h o edid d be lami h drochlo ide. d eh ylam f ma be y h ih. Pr visha e dirh lsuahid he o ide d he su hidiu hydrobromide, 1 ,3.-.di-otolylguanidine hydrochloride, 1,3- ;d -mto yl ni e .sa y a -c- 1y sua i h h t ere, c d me hy a no et nhen hydrochloride, methylaminomethylphenol hydrobromide, ordimethylamiemethylpheh l t e=di e h m n m h rh cit a e, e-diin thyl i hem y -ph y p e h rochloride, loal t y -smi emeth -p-1 ,3 t t hm l hbutylphenol hydrochloride and 2,4,6-tri-(dimethylaminoin thyhpheholtr h d h q In tre tin the c ubs it t am i n o mix ures of th ubs uted amm n um on di so e n ny su tab e p a s l en uch a Wa m y eehcl ethy a coho ixed so en can be emr oye s lu o em o d ca be of any i e conce a o from s little a eund m a to e s tura d solution, u p e e b n a concentration of a ou 1 0- toa ut ne an on a f molar- :amen ef h ti h ne s a y t treat t e y an obtai the bene i i esu t o hi e tihh ep dse ann he o we a le fo am t e un of play, the concentration of the treating soIutiQP, the po i y o the lay o y e e i d pth 0f tiqn .into the clay jbod-y-and the type of clay to be treated.

"in ene l, :th c ay is c nta te i h q u t 9 :s ituted amm n um ion i such amount a to p ovide M 1935 1 nd .Prefe ah y a as 5 il equ y lshts vi l ti u e amm um i p 'mii li h ale of base.- ehans capec ye thee ey- In an c se b s resu s! t inedi y us n an er -e uh ted ammo -measured as ;-mil l iequivalents, over the number of=;baseex hangep si i a so eas r as m qi i ent w w i em/example, th s luti ont i n th s st mtt mm h i n i-ca i e p te adj cen th orma w --forma tions to be trea e .a d; he h :P 'mi tw $09G" meate :the formatio p e u b ing used t f c th ;s0l uti0n intothe formation if .desired. :In addition, the

:soll t-ionansbe use to t ea a :o w nnat on e y spo t g, wo m-shoot ng.as fi ien amunt t e tiominra wellrbore :adjacent acsectiongto be -,shot,and--thgn shooting. .Also, in gun perforating .or jet perforating .a

:well, the solution can be spotted through the "ifltfil'H-LIO -be perforated i and the gun then inserted and fired :in (he hole opposite the interval. In secondary recovery, such as alxwater flood program, the treatingsolution can be used in front of the flood to stabilize the clay in the formation as the flood progresses through the formation, thus precluding a drop in injection rate caused by reduced permeability due to swelling and/or dispersing of the clay. In treating the formation adjacent a borehole of a well which is producing hydrocarbons, the beneficial results of this invention can be obtained by treating the formation with suflicient of the treating fluid to obtain a penetration of at least one foot and preferably between about 5 and 50 feet, and then returning the well to production.

' The mechanism involved in treating clays in accordance with our invention is an ion-exchange reaction between exchangeable cations of the clay and the substituted ammonium ions in the treating solution. When the clay is contacted with the substituted ammonium ions identified above, the substituted ammonium ions exchange quickly and in an essentially irreversible manner with the cations occupying the base-exchange sites on the clay structure. As a result of this treatment, hydrated, swollen clay will shrink essentially irreversibly, unhydrated clay will be rendered insensitive to Water and other swelling agents,'and the resistance of the clay to mechanical and chemical attack will be increased.

In order to demonstrate the effectiveness of the substituted ammonium ions identified above as'clay-stabilizing agents, we have run a series of tests in which various substituted ammonium ions were employed. The substituted ammonium ions were formed by dissolving in water salts obtained by the reaction of the basic aromatic nitrogen compound with hydrochloric acid. Montmorillonite was chosen as the clay for these tests because of its very high ability to swell and disperse. The tests comprised placing 0.077 gram of montmorillonite (0.077 milliequivalent base-exchange capacity) suspended in 5.0 milliliters of a salt solution in a test tube. One liter of the salt solution prior to suspending montmorillonite therein contained 2,317 milligrams of sodium bicarbonate, 279.9 milligrams of calicum chloride hydrate, 434.2 milligrams of magnesium chloride hydrate, and 0.86 milligram of magnesium sulfate. The contents of the test tube were allowed to set for 48 hours, after which the amount of precipitate was measured. The substituted ammonium ion was then added to the contents of the test tube in an amount equal to five times the base-exchange capacity of the clay and the mixture was shaken for minutes and subsequently allowed to stand for 24 hours. At the end of this period the volume of clay precipitate was estimated and such quantity of supernatant liquid was withdrawn from the test tube that the volume of the liquid and clay remaining was the same as the volume of the clay suspension originally treated. Fifteen milliliters of distilled water were added to the resulting mixture and the test tube was shaken for 15 minutes and allowed to stand for 24 hours, after which the volume of clay precipitate was again estimated. This cycle was repeated a number of times. At about the 15th test cycle and for one cycle only, a salt solution similar to that in which the montmorillonite was initially dispersed was substituted for the distilled water. Otherwise, the procedure was not changed. Each cycle results in a decrease in the salt concentration of the aqueous solution. and the concentration of treating agent in equilibrium with the clay precipitate. This dilution process will cause swelling and/ or dispersion of the clay if it hasnot been effectively stabilized. The substitution of the original salt solution for the distilled water at about the 15th test cycle is a test for the reversibility of the base-exchange reaction. Thus, if the treating agent is not held essentially irreversibly by the clay, part or all of it will be exchanged for sodium ions or other cations from the salt solution and the clay will swell and disperse in subsequent cycles of .distilled water leaching.

The results of these tests are tabulated below in Table l.

Table l Compound Cycles to Cycles to Colloidal Swelling Appesrand/or ance Dispersion N,N-dimethylbenzylamine hydrochloride- Dibenzylarnine hydrochloride Diphenylguanidine hydrochloride 1,3-di-o-tolylguanidine hydrochloride o-dimethylaminomethylphenol hydrochloride o -dimethylamiuomethyl-p-t-butylphenol hydrochloride o-dimethylaminomethyl-p-l,1,3,3-tetrarnethyln-butylphenol hydrochloride 2,4,6-tri-(dimethylaminomethy1)phenol trihydrochloride Ben zylamine hydro chloride 19 a a-methylbenzylamine hydrochloride 17 a N-phenylbenzylamine hydrochloride 18 a N ethyl-N -phenylbenzylamine hydrochloride 16 2 N-g1ethyl-N-phenylbenzylarnine hydrochlor- 7 2 i e 1 Tribenzylamine hydrochloride 4 8 Acetanilide hydrochloride 15 17 Phenylhydrazine hydrochloride 5 a p-benzylaminophenol hydrochlo 15 e Isopropoxydiphenylamine hydrochloride ,7 2 a-naphthylamine hydrochloride 19 a fi naphthylarnine hydrochloride. 19 a Benzidine dihydrochloride 22 a o-tolidine dihydrochloride 19 a N ,lzll ,N N-tetramethylbenzid ine dihydrochlo- 2 '2 C) denotes that the test was discontinued at the end of 24 cycles and no swelling. dispersion or colloidal appearance was noted.

(a) denotes that the test had a colloidal appearance at the cycle indicated in column A but had not swelled or dispersed at the end of 24 cycles.

In the above table, by colloidal appearance it is meant that after standing 24 hours the supernatant liquid retains a turbid or opalescent appearance characteristic of that caused by the scattering of incident light by suspended colloidal particles. The appearance of such a colloidal condition indicates that the clay has not been stabilized by the substituted ammonium ion tested. By .swelling it is meant that the settled volume of the clay at the end of 24 hours is at least 1V2 times the settled volume of the clay at the beginning of the test. By dispersion it is meant that the clay is dispersed uniformly throughout the liquid so that at the end of 24 hours no precipitate or sediment can be detected. Obviously, when the clay swells or disperses it has not been stabilized by the particular substituted ammonium ion tested.

The above table graphically illustrates the advantages of the present invention. Thus, it can be seen that many substituted ammonium ions derived from artomatic nitrogen compounds, e. g., benzylamine hydrochloride, amethylbenzylamine hydrochloride, N-phenyl-benzylamine hydrochloride, N-ethyl-N phenylbenzylamine hydrochloride, N-methyl-N-phenylbenzylamine hydrochloride, tribenzylamine hydrochloride, acetanilide hydrochloride, phenylhydrazine hydrochloride, isopropoxydiphenylamine hydrochloride, a-naphthylamine hydrochloride, B-naphthylamine hydrochloride, benzidine dihydrochloride, o-tolidine dihydrochloride and N,N,N,N'tetramethylbenzidine dihydrochloride are unsatisfactory as treating agents for stabilizing clays, for clays treated therewith were easily dispersed and resulted in aqueous solutions having colloidal appearance. Substituted ammonium ionsdcrived from N,N-

U dimethylbenzylamine hydrochloride, dibenz ylamine hydrochloride, diphenylguanidine hydrochloride, 1,3-di-otolyiguanidine hydrochloride, o-dimethylaminomethylphenol hydrochloride, o-dimethylaminomethyl-p-t-butylphenol hydrochloride, o-dimethylaminomethyl-p-1,1,3,3- tetramethyl-n-butylphenol hydrochloride, and 2,4,6-tri- (dimethylaminomethyl) phenol trihydrochloride, however, proved to be very effective for even at the end of 24 cycles the clay treated therewith was unaffected by water or the salt solution. 1

There follow illustrative embodimentsof the actual hydrochloride, p-benzylaminophenol practice of the process of this invention as applied to oil wells producing from formations containing clay. It is understood that the procedures described are illustrative and the invention not to be limited thereby.

In treating a formation adjacent the bottom of a boreholgtgstabi me the clay, said formation containing about percent. weight of montmorillonite and having a porosity of about per cent, so as to attain a radial depth oftreatment of at least 5 feet from the borehole, about 150 gallons of a one-molar aqueous solution of substituted ammonium ions derived from oeduncthylamino-methylp-t-butylphenol hydroehlor'de for e h foot of vertical hi kne s of th remain. to he ran t Wh e theoretically only e st sense 9 th a zq treatin solution wwld be as -dad tdrsat with a at the lay i the above volume of formation, an excess over the thsoreticalsuantity s stnslq sdts a sur ap d and plete reaction with the clay. The treating solution is introduced th a str n o atoll new Pip we e to withina few feet of the bottom of the hole and allowed to flow n by i S n the t e n olut on has a much higher specific gravity than water, oil orordinary Oil field Wi it wi d la e Wa e o oi oppo i e e formation to be treated and will then flow into. the formation- AS a aid n d lac n th t eat n sq u i n the formation, pressure can be employed. The treating solution is introduced into the formation slowly and allowed to remain in contact withthe format-ion for about 24 hours, after which the unused portion, along with produced fluid, is withdrawn from the well. It will be undertand t a in t ad o t ng fo ma adja en the bottom of a borehole, any selected formation interval above the bottom of the borehole can be treated in accordance with the invention by setting a bridge plug, in known manner, at the bottom of the formation to be treated, and thereafter proceeding as described above considering the top of the bridge'plug to be the bottom of the borehole.

The process of this invention is also used to advantage in secondary recovery operations wherein a displace- ;mcnt fluid such as water is applied under pressure to an oil-bearing formation by means of specially equipped input wells penetrating said formation for the purpose of'forcingthfe oil out of the oil-bearing formation through an output well penetrating said formation. Such operations are often developed in what is termed a fivespot-- pattern, with the producing well located in the center of a square formed by water input wells at the four corners. By introducing any of the treating solutions disclosed herein into the water input wells prior to injection of water, the treating solution will move ahead of the advancing water and thus stabilize the clay in the formation before the clay has had an opportunity to come in contact with the injection water and be deletcriously affected by contact therewith. In actual practice, the treating solution is placed adjacent the formation to be treated by introducing the same through a string of small diameter pipe lowered to a point adjaeent; the section of the formation to be treated in the manner described in the paragraph next preceding and is followed by normal injection of water. To establish a front of the treating solution about five feet thick (radially) ahead of the injection water at a radius of about feet from the borehole in a formation having the same montmorillonite content and porosity described shove, about 650 gallons of .a one-molar aqueous solution of o-dimethylaminomethyl-p-t-butylphenol hydrochloride is sufficient for each foot of thickness (vertical) of formation to be treated. Because of prior treatment in accordance with the iuventiql a satisfactory permeability of the clay during the water flood is maintained or improved, thereby leading to more 'efiicient The treating solutions herein disclosed are also entnlerq w h dvantage in. ell-well Pe fora in w while drilling.' Inwoll completions where such'fo'lw' tions are eased, off and the casing must be per'fsahl for production, the sealing property of clayovatorznfl can be detrimental. Since the hydrostatic head h mudin the borehole exceeds the formation pressure, wh- -thecasing is perforated the clay-water rnud rushes lab .the perforated formation until a mud cake seal is Ir tablished or the pressure is balanced. This often '8 locompanied by a fresh water loss tothe formation, wind in the clay formations described, swells the clay whirls is present. In addition, there often results block-ing. the perforated formation to such an extent that onmubsequent completion of the well the perforations have be washed or acidized with reagents known as clean out agents.

To. avoid such difficulties in perforating operational! accordance with the present invention, a string of tub is lowered into the borehole so that its lower adjacent the bottom of the section to be treated all about 300. gallons of a suitable oil-base drilling IIII is introduced through the tubing to displace the oilywaterdrilling mud' upwardly in. the borehole. Also L gallons of a one-molar aqueous solution of the M ing solution, e. g., o-dimethylaminomethyl-p-t buqb phenol hydrochloride, for each foot of thickness of the formation is thereafter introduced through the tub'llg and in turn displaces the oil-lbase drilling fluid upwarfly in the borehole. The perforating gun, either bullet n! jet, is then lowered into the. treating solution oppocin' the formation to. be treated and the casing perfo in the usual manner. The: hydrostatic head in thebolohole. exceeds the formation pressure and thus will for the treating solution. into the formation. In this way;

the naturally-occurring clay, which was exposed to fresh water lost;- to the formation from the clay-water drillil fluid, will be shrunken and stabilized and when the w is permitted toflow, or is swabbed orpumped, the \bused clay-stabilizing agent in the treating solution willbc produced from the format-ion. This operation will loan): the formation substantially free from plugging by and cake or other hydrated clay. Thus, by employing any one of the treating agents disclosed herein while plforating, the formation will be prevented from be mudded' off, the harmful effects of fresh water onmeurally-occurrin-gclaywill be nullified, the necessity for washing perforations wit-h'so-called mud acids will be eliminated, and the use of conventional clay-water dl'il ing muds will be permitted in areas where the producing formations contain swelling-type clays and the more expensive oil-base muds arecommonlyused. a

Similarly in oil well shooting in open hole with high explosives, such as nitroglycerine, trinitrotoluene, cm, the freshly exposed formation may also be contacted m'fll a clay-water drilling fluid: with the accompanying harmfuleffects described above. The drilling fluid opposite the formation to be treated: in such case can be mplaced with. an oil-basei drilling fluid followed by the treating solution in the manner described above, all the explosive can be lowered into the solution and dotsnated: in the customary manner. The beneficial results obtained inemployingithetreatingv solutions of the invention while. perforating will also accompany thein I: with high. explosives.

While we havev found that the specific substituted m monium ions disclosed herein or mixtures thereof as satisfactory for the purposes; of this, invention, there n certain. instances wherein it: is advantageous to; employ n: a ix u h rew th: the s bst u ed. mm n um is 9 s ec fica l d slo her nu h h av properties thereto, as. for example, the substituted an monium io dis losed in, ur q peu i sv app c ions filed q n ur ently herewith nr is tiw a NM 469,855 and 469,857 to 469,86l,'inclusive, as, welllnsin cause of the spatial configuration of their hydrophobic part, certain substituted ammonium ions will not be able to occupy these smaller sites, in which case it is advantageous to use one or more additional substituted ammonium ions of different spatial configuration which can occupy the remaining positions and thus complete the stabilization reaction. It is believed that this use is especially advantageous in the case of the mixed-layer clay minerals.

Obviously, many modifications and variations of the invention, as hereinabove set forth, may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. A method of stabilizing a clay-containing body which comprises contacting such clay-containing body with substituted ammonium ions derived from aromatic nitrogen compounds selected from the group consisting of N,N-dimethylbenzylamine, dibenzylamine, diphenylguanidine, 1,3-di-o-tolylguanidine, o-dimethylaminomethylphenol, o dimethylaminomethyl p t butyl phenol, o dimethylaminomethyl p 1,1,3,3 tetra methyl n butylphenol, and 2,4,6 tri (dimethyl aminomethyl) phenol.

2. A method of stabilizing a clay-containing body as in claim 1 in which the clay-containing body comprises at least one clay mineral selected from the class consisting of the montmorillonite group, hydrous-mica group, chlorite group, and kaolin group.

3. A method of stabilizing a clay-containing body which comprises contacting such clay-containing body with substituted ammonium ions derived from o di methylarnino methyl p t butylphenol.

4. A method of stabilizing a clay-containing body which comprises contacting such clay-containing body with substituted ammonium ions derived from o di methylamino methylphenol.

5. A method of stabilizing a clay-containing body which comprises contacting such clay-containing body with substituted ammonium ions derived from o di methylamino methyl p l,l,3,3 tertamethyl n butylphenol.

6. A method of stabilizing a clay-containing body which comprises contacting such clay-containing body with substituted ammonium ions derived from 2,4,6 tri (dimethylaminomethyl)phenol.

7. A method of stabilizing a clay-containing body which comprises contacting such clay-containing body with substituted ammonium ions derived from diphenylguanidine.

8. A method of stabilizing a clay-containing formation adjacent a well bore which comprises contacting such clay-containing formation with substituted ammonium ions derived from aromatic nitrogen compounds selected from the group consisting of N,N dimethyl benzylarnine, dibenzylamine, diphenylguanidine, 1,3 di o tolylguanidine, o dimethylaminomethylphenol, dimethylaminom ethyl p t butylphenol, o dimethyl aminomethyl p l,l,3,3 tetramethyl n butylphenol, and 2,4,6 tri (dimethylaminomethyl)phenol.

9. A method of stabilizing a clay-containing forma tion adjacent a well bore which comprises contacting such clay-containing formation with substituted ammonium ions derived from o dimethylaminomethyl p t butylphenol.

10. A method of stabilizing a clay-containing formation adjacent a well bore which comprises contacting such clay-containingformation with substituted ammoni urn ions derived from o-dimethylaminomethylphenol.

11. A method of stabilizing a clay-containing formation adjacent a well bore which comprises contacting such clay-containing formation with substituted ammonium ions derived from o dimethylaminomethyl p 1,l,3,3 tetramethyl n butylphenol.

12. A method of stabilizing a clay-containing formation adjacent a well bore which comprises contacting such clay-containing formation with substituted ammonium ions derived from 2,4,6 tri (dimethylamino methyl)phenol. I

13. A method of stabilizing a clay-containing formae tion adjacent a well bore which comprises contacting such clays-containing formation with substituted ammonium ions derived from diphenylguanidine.

. l4. A method of recovering oil from an oil-bearing formation containing clay, wherein a displacement fluid under pressure is applied to said formation through at least one input well penetrating said formation, and wherein oil is recovered from an output well pentrating said formation, which comprises introducing a treating solution containing substituted ammonium ions derived from aromatic nitrogen compounds selected from the group consisting of N,N dimethylbenzylamine, dibenz ylamine, diphenylguadidine, 1,3 di o tolylguanidine, o-dimethylaminomethylphenyl, o-dimethylaminomethyl-pt butylphenol, o dirn'ethylaminomethyl p 1,1,3,3 tetramethyl n butylphenol, and 2,4,6 tri (di methylaminomethyl)phenol into said input well, thereafter introducing said displacement fluid under pressure into said input well, forcing said treating solution through said formation by means of said displacement fluid, and recovering oil from said output well.

15. A method of recovering oil from an oil-bearing formation containing clay, wherein a displacement fluid under pressure is applied to said formation through at least one input well penetrating said formation, and wherein oil is recovered from an output Well penetrating said formation, which comprises introducing a treating solution containing substituted ammonium ions derived from o-dimethylaminomethyl-pt-butylphenol into said input well, thereafter introducing said displacement fluid under pressure into said input well, forcing said treating solution through said formation by means of said displacement fluid, and recovering oil from said output well.

16. A method of recovering oil from an oil-bearing formation containing clay, wherein a displacement fluid under pressure is applied to said formation through at least one input well penetrating said formation, and wherein oil is recovered from an output well penetrating said formation, which comprises introducing a treating solution containing substituted ammonium ions derived from o-dimethylaminomethylphenol into said input well, thereafter introducing said displacement fluid under pressure into said input well, forcing said treating solution through said formation by means of said displacement fluid, and recovering oil from said output well.

17. A method of recovering oil from an oil-bearing formation containing clay, wherein a displacement fluid under pressure is applied to said formation through at least one input well penetrating said formation, and wherein oil is recovered from an output well penetrating said formation, which comprises introducing a treating; solution containing substituted ammonium ions derived from o-dimethylaminomethyl-p 1,l,3,3 -tetrarnethy1- nbutylphenol into said input well, thereafter introducing;- said displacement fluid under pressure into said input well, forcing said treating solution through said formation by means of said displacement fluid, and recovering oil from. said output well.

18. A method of recovering oil from an oil-bearing: formation containing clay, wherein a displacement fluid under pressure is applied to said formation through at; least one input well penetrating said formation, and wherein ofl iereeoveredl from an output well penetrating said formation, which comprises introducing a treating solution containing substituted ammonium ions derived from 2,4,fi-tri tdimethylaminornethyl)phenol into said input well, thereafter introducing said displacement fluid under pressure into said input well, forcing said treating solution through said formation by means of said displacementfluid, and recovering oil from said output well.

RdmwCm in the tile of this patent UNITED STATES PATENTS Lietz i Nov. 11, Ralston et al May 25, Endersby May 9, Ratcliffe Jan. 2 1, Albaugh Apr. 29, Bond June 7, Jordan Nov. 28, Meadors June 3; Meadors July 15, Viles Aug. 19, Lytle Nov. 17,' Skinner June 14,

FOREIGN PATENTS Germany July 9", 

1. A METHOD OF STABILIZING A CLAY-CONTAING BODY WHICH COMPRISES CONTACTING SUCH CLAY-CONTAINING BODY WITH SUBSTITUTED AMMONIUM IONS DERIVED FROM AROMATIC NITROGEN COMPOUNDS SELECTED FROM THE GROUP CONSISTING OF N,N-DIMETHYLBENZYLAMINE, DIBENZYLAMINE, DIPHENYLGUANIDINE, 1,3-DI-O-TOLYLGUANIDINE, O-DIMETHYLAMINOMETHYLPHENOL, O - DIMETHYLAMINOMETHYL - P - T - BUTYLPHENOL, O - DIMETHYLAMINOMETHYL - P - 1,1,3,3 - TETRAMETHYL - N BUTYLPHENOL, AND 2,4,6 - TRI - (DIMETHYLAMINOMETHYL) PHENOL. 